Damper device for a piston pump

ABSTRACT

The invention relates to a damper device for a piston pump. The device includes a partly air-filled, upright tube ( 1 ) placed on the inlet conduit ( 2 ) of the piston pump, and a partly air-filled, upright tube ( 3 ) placed on the outlet conduit ( 4 ) of the piston pump. The two upright tubes ( 1, 3 ) are interconnected with each other by means of a tube ( 5 ) on which a shut-off valve ( 6 ) is disposed. Each of the upright tubes ( 1, 3 ) is connected to a blower valve ( 7, 8 ), respectively. Both of the blower valves ( 7, 8 ) are connected to a common compressed air source. The damper device may be adapted in a simple manner for aseptic operation and/or elevated product pressure.

FIELD OF THE INVENTION

[0001] The present invention relates to a damper device for a pistonpump comprising a partly air-filled, upright tube placed on the inlet ofthe piston pump, and a partly air-filled upright tube placed on theoutlet of the piston pump, both upright tubes being mutuallyinterconnected by means of a shut-off valve.

BACKGROUND OF THE INVENTION

[0002] A piston pump is a high pressure pump of the positivedisplacement variety which substantially consists of a powerful electricmotor, transmission mechanism and crank mechanism, as well as a pumpassembly with a pump block, valves and a number of plungers or pistons.The rotary movement from the electric motor is converted by means of thetransmission mechanism into the reciprocating movement of the pistons.

[0003] One common field of practical application for a high pressurepump of the piston type is in a homogenizer. In those cases where thehigh pressure pump is employed as a homogenizer, the pump block issupplemented with one or more homogenization apparatuses orcounter-pressure apparatuses in which the homogenization process propertakes place.

[0004] Homogenization is an often-employed industrial process, above allwithin the dairy industry, where homogenization is employed forsplitting the fat globules in milk and thereby preventing cream setting.Almost all consumer milk is homogenized today. This employment withinthe food industry entails that extremely stringent demands on hygieneare placed on not only the homogenizers but also all ancillaryequipment.

[0005] The movement of the piston pump implies that, on the suction sideof the pump, a liquid column of product such as milk is to beaccelerated on each stroke of the piston. This entails that the productflow will be greatly pulsating and, in order to avoid the risk that thisdamages the pump and ancillary equipment, it is necessary to provide thepiston pump with dampers.

[0006] In its simplest form, a damper consists of a partly air-filledupright tube in direct connection to the piston pump. Many homogenizersavailable on the market feature as standard such dampers on both thesuction side and the pressure side of the pump.

[0007] In most practical applications, the above-described type ofdamper is efficient from the point of view of damping, but cannotnormally be cleaned in the CIP system of the dairy plant (Cleaning InPlace). The upright tube section must be dismounted and washed manually.Nor is such a damper suitable for aseptic applications, since theupright tube is difficult to sterilize in connection with thesterilization of the remaining equipment.

[0008] Gradually as such a damper is in operation, the air entrapped inthe upright tube will, in due course, be “consumed” by the product flow.It has hitherto not been possible to replenish air while the plant is inoperation, but it has instead been necessary to stop production, whichhas entailed both time losses and losses of product.

[0009] Requirements on higher output capacities and longer runningtimes, for example within the food industry, as well as the utilisationof higher pressure on the pressure side of the pump entail that theabove-described dampers will attain far too short an operational runningtime. The air in the upright tubes is consumed rapidly and productionstoppages become necessary.

[0010] There are also on the market a number of other types of dampers.Membrane dampers display a gas-filled space discrete from the product bythe intermediary of a membrane. These dampers are expensive inoperation, since the membrane often needs to be replaced. There are alsospecialist dampers which can be shut off and emptied of product,whereafter the air can once again be replenished. However, this entailsnot inconsiderable product losses.

[0011] Specialist inlet dampers provided with an external steam hatinvolve many parts which are difficult to clean and which may causeproblems with regard to sterility in aseptic plants. Another type ofdamper is the resonator type which suffers from the drawback of beingdifficult to clean and thereby not suitable for food applications.

OBJECT OF THE INVENTION

[0012] One object of the present invention is to realize a damper whichmay be employed on both the inlet and the outlet of a piston pump or ahomogenizer. The damper may also be adapted to the high pressures whichmay prevail.

[0013] A further object of the present invention is to realize a damperwhich is fully washable using the washing system which is employed forremaining equipment, i.e. in a dairy plant.

[0014] Yet a further object of the present invention is that the dampersmay be supplied with fresh air during operation, which contributes infewer production stoppages and reduced product losses caused by thedampers.

[0015] Still a further object of the present invention is that thedamper may, in a simple manner, be adapted to aseptic applications.

SUMMARY OF THE INVENTION

[0016] These and other objects have been attained according to thepresent invention in that the damper of the type described by way ofintroduction has been given the characterising feature that a blowervalve is connected to each upright tube, the blower valves being in turnconnected to an air supply source.

[0017] Preferred embodiments of the present invention have further beengiven the characterising features as set forth in the appendedsubclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One preferred embodiment of the present invention will now bedescribed in greater detail hereinbelow, with reference to theaccompanying Drawings, in which:

[0019]FIG. 1 is a schematic illustration of a damper according to thepresent invention; and

[0020]FIG. 2 is, partly in section, a side elevation of a blower valveaccording to the present invention.

[0021] The accompanying Drawings show only those details and partsessential to an understanding of the present invention, and both pistonpump/homogenizer and other equipment included in the plant have beenomitted.

DETIALED DESCRIPTION OF THE INVENTION

[0022]FIG. 1 is a schematic illustration of a damper device for a pistonpump or a homogenizer (the piston pump or homogenizer is not shown onthe Drawings) according to the present invention. The damper deviceincludes a partly air-filled upright tube 1 which is placed on a tube 2constituting the inlet of the piston pump. The damper device alsoincludes a partly air-filled upright tube 3 which is placed on a tube 4constituting the outlet of the piston pump. Normally, the damper deviceis integral with the homogenizer or the piston pump.

[0023] The two upright tubes 1 and 3 are interconnected to one anotherby means of a tube 5 on which a shut-off valve 6 is disposed. Theshut-off valve 6 is mounted so that it may serve partly as a safetyvalve and partly as a valve which may open a communication between thetwo upright tubes 1, 3. If a stoppage were to occur in the outlet tube 4of the piston pump, the shut-off valve 6 opens and, in this state,constitutes a safety valve.

[0024] The shut-off valve 6 is also opened on washing and onsterilisation. For example, the piston pump or the homogenizer may beincluded in a dairy plant and is then connected to the washing system ofthe plant, a so-called CIP system (Cleaning In Place). This implies thatboth of the upright tubes 1 and 3, the inlet tube 2 of the pump, itsoutlet tube 4, as well as the tube 5 between the two upright tubes 1 and3 with the shut-off valve 6 are washed. If the'plant is an asepticplant, the components included in the plant are sterilized prior toproduction. Sterilisation is put into effect using hot water and in thesame manner as the CIP washing.

[0025] A blower valve 7, 8, respectively is also connected to eachupright tube 1, 3. The blower valves 7, 8 may, as in FIG. 1, be placedrelatively far down on the upright tube 1, 3, or alternatively may beplaced higher up on the upright tube 1, 3. The blower valves 7 and 8 maybe designed in the manner which is apparent from FIG. 2.

[0026] The blower valve 7, 8 (FIG. 2) has an inlet 9 for air or steamand an outlet 10 connected to one of the upright tubes 1, 3. The blowervalve 7, 8 is sealingly connected to an upright tube 1, 3. The blowervalve 7, 8 is also connected to some type of overflow valve 12, 13through an outlet 11. Between each blower valve 7, 8 and the overflowvalve 12, 13, there is disposed a shut-off valve 14, 15. The shut-offvalves 14, 15 are employed to close the outlet when air is fed to eachrespective upright tube 1, 3 via the blower valve 7, 8. In those caseswhen the damper device is employed for low pressure and in a non-asepticplant, the overflow valves 12, 13 can be replaced by some form ofthrottle valve or throttle washers.

[0027] The inlet of the blower valves 7, 8 is connected to some form ofjoint compressed air source (not shown). On each inlet conduit, thereshould suitably be provided a shut-off valve 16, 17 so that one blowervalve 7, 8 at a time can be supplied with air. The air in the compressedair source must be pure, food-approved air. Available air pressure fromthe compressed air source should be approx. 1 bar higher than thehighest product pressure in the plant together with which the damperdevice is employed.

[0028] In those cases where the damper device is to be employed for highpressure, a booster 18 is required which compresses the incoming air andensures that the air pressure into the blower valves 7, 8 will besufficiently high. The booster 18 has an intake air conduit 19 forcontrol air and an intake air conduit 20 for supply air. On the conduit21 out from the booster 18, there is suitably provided a pressure gauge22 and, in those cases where the damper device is to be employed in anaseptic plant, there is also a check or non-return valve 23 and ashut-off valve 24.

[0029] In those cases where the damper device is intended for an asepticapplication, steam is supplied to the blower valves 7, 8. The ingoingair into the device should maintain a pressure of approx. 1.5 bar inorder to ensure aseptic conditions. The steam conduit 25 should suitablybe provided with a pressure gauge 26, a check or non-return valve 27 anda shut-off valve 28. The non-return valve 27 is to prevent air fromentering into the steam conduit 26 in the same manner that thenon-return valve 23 on the air conduit 21 is to prevent steam fromentering into the air conduit 21. For an aseptic plant, a sterile filter29, for example a membrane filter, is also required through which theair passes in its way into the blower valves 7, 8. The sterile filter 29is kept aseptic by the supply of steam.

[0030] The supply of air also takes place at specific intervals whoselength may vary and depend upon the process for which the damper deviceis employed. Alternatively, some form of sensor may be employed forindicating the level of the air entrapped in the upright tube 1, 3. Byemploying one of the shut-off valves 16, 17 alternatingly, air is fedinto one upright tube 1, 3 at a time. The air enters into the blowervalve 7, 8 through the inlet 9 and the valve 7, 8 opens into the uprighttube 1, 3 in that the valve cone 30 opens the outlet 10. As a result ofthe design of the valve cone 30, only a narrow gap is opened in to theupright tube 1, 3.

[0031] In the event the damper device is employed for high pressure, theshut-off valve 14, 15 should be closed for the outlet 11 and for thatblower valve 7, 8 which is in the process of being replenished. In anaseptic plant, the valve 28 for steam supply is closed.

[0032] In order to ensure the aseptic conditions when the damper deviceis employed in a sterile plant, steam must always be supplied to theblower valves 7, 8 when these are not being used for replenishing air tothe upright tubes 1, 3. When the air replenishment is completed, thevalve 24 for air closes and the valve 28 opens. Both the valves 16, 17on the inlet conduits to the blower valves 7, 8 and the valves 14, 15 onthe outlet conduits must be open. The valve cone 30 of the blower valve7, 8 closes the outlet 10.

[0033] The steam which enters into the blower valves 7, 8 enters inthrough the inlet 9 and passes through the steam gap 31 in orderthereafter to depart from the blower valve 7, 8 through the outlet 11.The blower valve 7, 8 may also be purged of the steam which condenses inthe valve 7, 8 through the gap 32.

[0034] The overflow valve 12, 13 may consist of a counter-pressurevalve, or alternatively a thermodynamic steam trap. By maintaining acertain excess pressure of the steam, an efficient obstacle will becreated for ensuring aseptic conditions in the blower valve 7, 8. Theoverflow valve 12, 13 also serves as a leakage indicator in the eventleakage were to occur in the sealing connection 10 to the upright tube1, 3. The conduits in to the blower valves 7, 8 and the sterile filter29 being sterile as a result of the supply of steam, that air which isfed to the upright tubes 1, 3 on each replenishment occasion will besterile.

[0035] As will have been apparent from the foregoing description, thepresent invention realizes a damper device for a piston pump or ahomogenizer which may be employed on both the inlet and the outlet tothe piston pump, in that the damper device is adapted for the elevatedpressures which may occur at the outlet. Furthermore, the damper deviceis designed so that air may be replenished to the upright tubes duringoperation, which minimizes production stoppages and thereby reduces anypossible product losses caused by dampers. The damper device is welldesigned for hygienic applications and may readily be adapted foraseptic plants.

1. A damper device for a piston pump comprising a partly air-filled,upright tube placed on the inlet of the piston pump, and a partlyair-filled upright tube placed on the outlet of the piston pump, bothupright tubes being mutually interconnected by means of a shut-offvalve, wherein each upright tube is connected to a blower valve, saidblower valves being in their turn connected to an air supply source. 2.The damper device as claimed in claim 1, wherein the blower valve hasone outlet sealingly connected to an upright tube and one outletconnected to an overflow valve.
 3. The damper device as claimed in claim2, wherein the damper device is adapted to aseptic operation by theblower valves and a sterile filter being connected to a supply of steam.4. The damper device as claimed in claim 3, wherein the air supply isconnected to the sterile filter.
 5. The damper device as claimed inclaim 2, wherein the damper device is adapted for an elevated pressurein that a booster is placed on the air conduit.